Top latch select liner with tailpipe and method of installing

ABSTRACT

A top latch select liner is shown which provides for the attachment at the top of a select liner of large pipe assemblies for use in solution mining operations. A method of lowering tailpipes of heavy construction safely into a solution mining cavity is also shown which involves the use of casing fluid and hydraulic pressures so that the pipes can be lowered on wire lines.

[4 1 Jan. 25, 1972 United States Patent Porter References Cited [54] TOP LATCH SELECT LINERWITH TAILPIPE AND METHOD OF INSTALLING UNITED STATES PATENTS e S u R Tausch 728 566 999 mmm 2002 446 06 69 233 a m w n 6 m it we a ms w m." m ML k mm mm h .C m .m mm SK me n n8 e VS .mA 1 23 77 [1 Canada Primary Examiner-Ernest R. Purser Attorney-Chisholm and Spencer [22] Filed: Dec. 8, 1969 [57] ABSTRACT A top latch select liner is shown which Appl. No;

provides for the atlarge pipe assemblies tachment at the top of a select liner of ............................E21.?Z5 mei'm'ufimmimn .166/153, 155, 156, 208, 315;

tailpipes of heavy construction safe] cavity is also shown which involves hydraulic pressures so that the pip lines.

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ATTORNEY 5 TOP LATCH SELECT LINER WITI-I TAILPIPE AND METHOD OF INSTALLING BACKGROUND OF THE INVENTION In the solution mining of mineral deposits in which a solvent for the mineral located in the deposit is introduced into a borehole and cavities of substantial size are created therein by the dissolution of the mineral deposits, it is desirable to position within the cavity during the solution mining operation tailpipes of varying lengths. Typically, tailpipes are attached to select liners which are affixed to the casing wall in the borehole so that the tailpipes terminate at some given distance in the subterranean cavity formed during the dissolution of the mineral deposits. One of the difficulties encountered in suspending tailpipes from select liners is vertical movement of these liners caused by the weight of the tailpipes. This weight is normally considerable, several thousand pounds or more. This inability of the select liners to maintain their position within the casing is due to the weight pull of the tailpipe attached to the liners. In conventional operations tailpipes are mounted at the base of a select liner and are suspended therefrom. Quite frequently the weight of the liner and presv sure differentials are such that it causes the select liner to collapse completely. This movement of select liners within casings disturbs the positioning of tailpipes within cavities or may even cause tailpipes to fall into a cavity in the case of a complete collapse of a select liner. Neither of these conditions is tolerable in a solution mining operation. Also, because of these problems caused by the weight of tailpipes and pressure differentials exerting forces on select liners, tailpipes must necessarily be restricted in size in solution mining operations. Thus, tailpipes must be reduced in length, diameter and weight, so that movement of select liners will not occur.

THE PRESENT INVENTION In accordance with the instant invention a mechanical seal and latch assembly is designed and built to suspend the tailpipe from the top end of a select liner. With the method of the instant invention, the select liner is set in the bore hole at some convenient distance above the cavity roof. A tailpipe is then run through the hole and into the cavity through the select liner and the top end of the tailpipe is landed with a setting sub which seals and latches it into a landing ring on top of the select liner. At this landed position the bottom end of the pipe is positioned at a desired distance from the bottom of a cavity or a withdrawal point for solvent from a solution mining cavity. By suspending the tailpipe from the top end of the select liner, the select liner is capable of supporting a considerable load, for example, a load in excess of 30,000 pounds. Supported from the top of the select liner, the weight of the tailpipe tends to compress the liner and the liner can then support a relatively long, heavy tailpipe which will permit the utilization of tailpipes of much more rugged construction and size. In addition, in utilizing the instant invention with flow in the normal direction, that is up through the tailpipe, the pressure remains equalized across the select liner. Thus, there is no tendency to collapse the select liner. Select liners which have had tailpipes suspended from the bottom of the liner have resulted in pressure differentials existing across the select liner during well operation in solution mining application. This differential was approximately equivalent to the fluid pressure drop from the bottom to the top of the tailpipe. This pressure differential resulted frequently in a collapsed select liner and failure of the tool to perform in the cavity as required.

As a further embodiment of the instant invention a method is provided for safely lowering tailpipes into well casings when the tailpipe is of considerable size and weight. In this embodiment the tailpipe is typically plugged to prevent fluid flow therethrough. The setting sub associated with the tailpipe is supplied with a channel member on its exterior surface in which a gasket of any given external diameter can be fitted. The gasket is used in this manner to adjust the clearance between the casing in which the setting sub and tailpipe are running and the outside surface of the gasket or O-ring. Since in solution mining operations the casings are filled with fluid, control of the clearance between the casing wall and the outer wall of the gasket or O-ring effectively serves to control the rate of descent of the setting sub and associated tailpipe. With this arrangement, tailpipes weighing as much as 30,000 pounds can be lowered on a wire line while typically a limit of 1,500 pounds would be placed on lowering a tailpipe on a wire line in the conventional manner.

The invention will be more readily understood by reference to the accompanying drawing in which:

FIG. 1 is a detailed drawing of the setting sub, landing ring, select liner and tailpipe of the instant invention and,

FIG. 2 is a diagrammatic illustration of a tailpipe which has been run into a borehole and landed onthe landing ring.

Turning to FIG. 1, there is shown a casing 1 having positioned therein a setting sub 2 and a landing ring 3. Landing ring 3 has associated therewith a latching device 4 which is actuated by a circumferential helical spring 11 and landing ring 3 is also externally threaded at 5 so-that it can be attached to a select liner 6. The setting sub 2 is provided at its lower end with external threads 7 which are utilized to engage the upper end of the tailpipe 8. The movement of the setting sub 2 through the landing ring 3 moves the latches 4 outwards. Once the setting sub 2 is seated on the landing ring 3, the latches engage the latch groove 13 on the setting sub 3 and thus prevent its movement up out of its set position from fluid flow. O-rings 14 which are installed on the setting sub 3 engage a cylindrical polished seal seat in the landing ring and thus flow of effluent between the landing ring and setting sub is prevented. The groove 15 in the upper part of the setting sub 2 is used by the setting tool (not shown) which tool is conveniently carried on a wire line. The setting sub 2, landing ring 3 and select liner 6 are removed by inserting a setting tool in the groove 15 and applying vertical force sufficient to overcome the weight of the tailpipe and select liner drag.

In providing for the setting of a tailpipe 8 in the bore hole associated with casing l, the select liner 6 is placed against the casing l in the conventional manner with the landing ring 3 in pIace when the select liner is so placed. Packer cup mandrels may be used to seal the select liner 6 to the casing, special liners such as described in U.S. Pat. No. 3,391,962 may be employed or attachments such as shown in U.S. Pat. No. 3,152,643 may be utilized to affix the liner 6 to the wall of casing 1. In particular, the present invention is especially useful when used in conjunction with select liners such as described in U.S. Pat. No. 3,391,962 and illustrated in FIG. 1 herein. The landing ring 3 is threaded into the upper portion of the select liner 6 using the internal threads 5 located on the lower end of the landing ring 3 and as stated above usually prior to placing the liner in the casing l. The tailpipe 8 is affixed to the lower end of the setting sub 2 by the threads 7 on the interior of the tailpipe 8 and the exterior of the end of the setting sub 2 The length of the tailpipe is chosen to place the lower end of the tailpipe in the subterranean cavity (not shown) associated with the borehole of casing l a desired distance into the cavity and above the floor thereof. As will be readily understood, when in place, the force exerted by the weight of the tailpipe 8 is applied to the top of the select liner 6 and tends to compress it, thus forcing it against the wall of the casing 1 thereby rigidly mounting the select liner 6 thereon. .This application of downward force on the top of the select liner caused by the weight of the ta lpipe permits the use of heavier tailpipes than would be possible if the tailpipe was mounted on the lower end of the select liner as shown in U.S. Pat. No. 3,39] ,962 for example.

A diagrammatic illustration of the setting sub and landing ring with the select liner attached and the tailpipe traversing the entire device is shown in FIG. 2.

As stated above a further embodiment of this invention involves a method of lowering tailpipes into cased boreholes. In this embodiment of the invention the setting sub 2, with a tailpipe 8 attached thereto is run into the casing l. The exterior of the upper end of the setting sub 2 is provided with a notch 9 which is adapted to receive a gasket or O-ring 12 as shown in phantom in FlG. l. in the normal operation of this embodiment the O-ring orgasket controls the spacing between the casing wall and the wall formed by the gasket. The tailpipe 8 is plugged at its lower end with a plug or sealing member (FIG. 2) which prevents fluid flow in an upward direction into the interior of the tailpipe 8. The lowering of the tailpipe through the fluid filled casing l is thus correlated in rate by regulating with the gasket or O-ring the space between this element and the casing wall. in this manner the tailpipe and setting sub 2 can be floated down gently through the casing until the setting sub 2 engages the landing ring 3. Operating in this manner, on a simple wire line, tailpipes weighing thousands and thousands of pounds, for example, 10,000 or more pounds can be lowered into a solution mining cavity and firmly latched to a liner on its upper end without serious difficulty. The wire lines for lowering such weights need not be strong enough to support the weight of the tailpipe 8 since the fluid pressure working against the plugged tailpipe absorbs the bulk of the downward force caused by the weight of the tailpipe. Once the tailpipe is set in the hole in accordance with the practice of this embodiment, fluid flow is reversed in the tailpipe for a short period of time to dislodge the plug located in the terminal end of the tailpipe. Once the plug is dislodged,

the flow of liquid through the tailpipe can be regulated in either direction.

As will be readily understood by the skilled art utilizing the methods and apparatus of the instant invention, large tailpipes can be lowered into solution mining cavities without causing collapse of a select liner associated therewith. Positioning the tailpipe above the select liner in a landing ring using the setting sub of the instant invention, permits the utilization of large, heavy and rugged tailpipes, without any attendant movement of select liners once they are in place. Further, in practicing the instant invention, large tailpipes can be lowered into a solution mining cavity through a borehole casing on simple, light gauge wire lines since the application of the method claimed herein permits the use of hydraulic pressure as the means to absorb the weight forces in the downward direction caused by the tailpipes.

While the invention has been described with respect to certain illustrative embodiments, it is not intended to be so limited except insofar as appears in the accompanying claims.

lclaim:

l. A method of introducing a tailpipe into a cased borehole having fluid therein comprising attaching a tailpipe to a setting sub constructed and arranged to engage a landing means positioned in said casing and having a liner assembly associated therewith, plugging said tailpipe at the lower end thereof, establishing a fixed clearance between the casing and the setting sub, introducing the tailpipe and setting sub into the casing and thereby controlling the downward movement of the setting sub and attached tailpipe.

2. A method of positioning a conduit in a subterranean cavity comprising, providing a liner in a cased borehole a fixed distance above said cavity, providing on the upper end of said liner a setting sub-engaging means, introducing into said cased borehole a setting sub having a fluid conduit affixed to it and provided with means to couple with said setting sub-engaging means, controlling the descent of the fluid conduit in said cased borehole by establishing a circumference on the setting sub providing a fixed clearance between the setting sub and the casing to thereby control hydraulic pressure applied upwardly on said setting sub and associated conduit by fluid present in said cased borehole at a value such that the rate of descent of the conduit in the cased borehole is maintained at a desired value.

3. Apparatus suitable for use in solution mining a subter ranean cavity comprising a liner, constructed and arranged to be mounted in a borehole, means at the upper end of said liner for engaging a landing rin a landin rin affixed to said liner, a latch member associate with said an mg ring, a setting sub provided on an upper portion thereof with an expanded shoulder adapted to engage the upper end of said landing ring, the lower end of said setting sub being tapered in part so that it passes through said landing ring and means at the end of said setting sub for engaging a fluid conduit, said setting sub and fluid conduit being in fluid communication with each other when engaged. 

1. A method of introducing a tailpipe into a cased borehole having fluid therein comprising attaching a tailpipe to a setting sub constructed and arranged to engage a landing means positioned in said casing and having a liner assembly associated therewith, plugging said tailpipe at the lower end thereof, establishing a fixed clearance between the casing and the setting sub, introducing the tailpipe and setting sub into the casing and thereby controlling the downward movement of the setting sub and attached tailpipe.
 2. A method of positioning a conduit in a subterranean cavity comprising, providing a liner in a cased borehole a fixed distance above said cavity, providing on the upper end of said liner a setting sub-engaging means, introducing into said cased borehole a setting sub having a fluid conduit affixed to it and provided with means to couple with said setting sub-engaging means, controlling the descent of the fluid conduit in said cased borehole by establishing a circumference on the setting sub providing a fixed clearance between the setting sub and the casing to thereby control hydraulic pressure applied upwardly on said setting sub and associated conduit by fluid present in said cased borehole at a value such that the rate of descent of the conduit in the cased borehole is maintained at a desired value.
 3. Apparatus suitable for use in solution mining a subterranean cavity comprising a liner, constructed and arranged to be mounted in a borehole, means at the upper end of said liner for engaging a landing ring, a landing ring affixed to said liner, a latch member associated with said landing ring, a setting sub provided on an upper portion thereof with an expanded shoulder adapted to engage the upper end of said landing ring, the lower end of said setting sub being tapered in part so that it passes through said landing ring and means at the end of said setting sub for engaging a fluid conduit, said setting sub and fluid conduit being in fluid communication with each other when engaged. 